The images are graphically clear: Small piglets being hurled to a concrete floor; large, fully grown sows gnawing the bars on their tiny cages; pigs with open sores lying untended on the ground; piglets squealing as their tails are cut off without benefit of anesthetic; and workers tossing live piglets back and forth and describing them as "bouncy."

All were among the images on undercover video just released by the animal rights nonprofit Mercy for Animals, capturing production at Iowa Select Farms, the state's largest pig farm, and prompting some retailers to suspend purchases of pork from the company.

Gaining access as employees, "our investigators go in as eyes and ears for the public," said Nathan Runkle, executive director of Chicago-based Mercy for Animals. "They give their real names and real social security numbers and they shoot the video with a small undercover camera. Part of our message is there is not a single federal law that provides protection to factory animals. What we need are stricter, stronger laws."

The Iowa Falls-based company says it is investigating the alleged incident at it's facility in Kamrar, Iowa.

Runkle said the video was shot between April and June and that the facility was selected at random. "We did not have insider information about abuse ... but we found these kind of ugly practices rampant at this facility," he said of the allegations.

Runkle conceded that some of what he describes as abuse is "standard industry practice" in the pork industry. For instance, gestation crates are widespread within the pig farming industry. Sows spend most of their lives in a tiny space where they can't lie down or turn around, producing litter after litter of piglets until they die.

Seven states have already banned gestation crates but Iowa Select Farms continues to use them. "If anyone subjected dogs or cats to this kind of treatment, they would be arrested," Runkle said.

Iowa Select Farms is the fourth largest pork producer in the nation. It supplies pork to JBS Swift (Swift Pork Co.), which, in turn, sells products to some of the biggest retailers in the nation such as Costco, Safeway and Kroger.

Safeway issued a statement Tuesday calling the images "disturbing" and said it had immediately "halted purchases from JBS Swift while a thorough investigation is conducted into the operation of Swift's supplier, Iowa Select Farms.

Likewise, Kroger said it was "concerned" and had asked JBS Swift to "suspend supplying product to Kroger from the facility that is shown in the video."

Craig Wilson, a vice president at Costco Wholesale, called the images "terrible" but said the company had no plans to suspend shipments of pork from Swift, preferring instead to "give them [Iowa Select Farms] an opportunity to knock it off and make things right."

In addition, Wilson said he had heard some of the scenes in the video might have been "staged," a claim that Runkle of Mercy for Animals called "ridiculous, absolutely untrue and not supported by reality."

For its part, Iowa Select Farms posted a statement from the company veterinarian, Dr. Howard Hill, on its website. "Iowa Select has a long-standing commitment to animal welfare. ...We have already initiated an investigation into the portions of the video that show unacceptable animal handling by a few employees."

The statement goes on to condemn anyone who would "video tape what they believe is animal abuse if they had a chance to stop it."

This is not the first hidden camera investigation launched by Mercy for Animals and it won't be the last, Runkle said.

"Most of this abuse takes place in secret and the animals are left to pay the hidden price," he said of the allegations. "As a civilized society, it is our moral obligation to do something about it. Profit should not be an excuse for animal cruelty."